JP4556310B2 - Method for producing aluminate phosphor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an aluminate phosphor suitably used for various light emission type displays such as a plasma display panel (hereinafter referred to as “PDP”) and vacuum ultraviolet ray excited light emitting elements such as rare gas lamps.
[0002]
[Prior art]
In recent years, development of a vacuum ultraviolet light-excited light-emitting element having a mechanism for exciting phosphors to emit light with vacuum ultraviolet light emitted by rare gas discharge has been actively performed. A typical example is the development of PDP. The PDP is a flat panel display capable of increasing the size of a screen, which is difficult to achieve with a cathode ray tube (CRT) or a color liquid crystal display, and is expected for display in public spaces and for large-screen televisions. The PDP is a display element configured by arranging a large number of minute discharge spaces (hereinafter sometimes abbreviated as “display cells”) in a matrix. A discharge electrode is provided in each display cell, and a phosphor is applied to the inner wall of each display cell. A space in each display cell is filled with a rare gas such as He—Xe, Ne—Xe, Ar, etc., and by applying a voltage to the discharge electrode, a discharge occurs in the rare gas, and vacuum ultraviolet rays are emitted. . The phosphor is excited by the vacuum ultraviolet rays and emits visible light. An image is displayed by designating the position of the display cell that emits light. By using phosphors that emit light of the three primary colors of light, blue, green, and red, full color display can be performed.
[0003]
There is a rare gas lamp as a vacuum ultraviolet light-excited light emitting element other than PDP. The rare gas lamp is a lamp that generates vacuum ultraviolet rays by discharge in a rare gas and emits light by a mechanism that converts the vacuum ultraviolet rays into visible light by a phosphor. Since rare gas lamps do not use mercury, they are attracting attention from the viewpoint of environmental issues.
[0004]
An aluminate phosphor excited by vacuum ultraviolet rays or the like emitted by discharge in a rare gas has already been proposed. As the blue light emitting phosphor, a compound containing a composite oxide represented by the composition formula x ¹ M ¹ O · y ¹ MgO · z ¹ Al ₂ O ₃ as a base and Eu as an activator has been proposed, Typical examples include compounds in which M ¹ is Ba (BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₄ O ₂₃ : Eu, etc.). As the green light emitting phosphor, a compound containing a complex oxide represented by the composition formula x ¹ M ¹ O · y ¹ MgO · z ¹ Al ₂ O ₃ as a base and Mn as an activator has been proposed, Typical examples include compounds in which M ¹ is Ba (BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, etc.).
[0005]
The aluminate phosphor is generally reduced by mixing a compound containing a metal element constituting the target aluminate phosphor at a predetermined ratio so that the target aluminate phosphor is produced. It can be obtained by firing in an atmosphere. For example, an aluminate phosphor represented by the composition formula Ba _0.9 Eu _0.1 MgAl ₁₀ O ₁₇ has a barium compound, a europium compound, a magnesium compound, and an aluminum compound as Ba: Eu: Mg: Al = 0.9: 0.1. It can be manufactured by mixing at a ratio of 1:10 and firing the resulting mixture in an atmosphere containing hydrogen, ie, an atmosphere having a reducing property.
[0006]
When a display cell such as a PDP is manufactured using these phosphors, high emission luminance is required. A phosphor used for a display cell such as a conventional PDP has a primary particle diameter of about 2 to 5 μm and is applied to the back plate side of the display cell, that is, the side surface and the lower surface of the display cell. Recently, in order to further increase the light emission luminance of the PDP, it has been required to apply the phosphor particles not only on the side surface and the bottom surface of the display cell in the PDP, but also on the front plate side, that is, the upper surface of the display cell. Therefore, there is a demand for phosphor particles having a particle size suitable for satisfying these requirements and having high emission luminance.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide an aluminate phosphor having a particle size suitable for various types of light emission type displays such as PDP and vacuum ultraviolet light-excited light emitting elements such as rare gas lamps and having high emission luminance, and a method for producing the same. There is.
[0008]
[Means for Solving the Problems]
As a result of intensive research under these circumstances, the present inventors have obtained that the aluminate phosphor produced using α-alumina having an average primary particle size within a certain range as a raw material has high emission luminance. Suitable for phosphors used in various types of light-emitting displays such as PDP and vacuum ultraviolet-excited light-emitting devices such as rare gas lamps, and aluminate phosphors with a small average primary particle size and few coarse particles The present invention was found to be highly suitable for applications requiring good adhesion and transmission of visible light, such as when attaching a phosphor layer to the front plate of a PDP. It came to do.
[0009]
That is, the present invention provides a method for producing an aluminate phosphor (excluding an aluminate phosphor for a phosphorescent material) using an α-alumina powder having an average primary particle size of 0.05 μm or more and less than 0.3 μm as a raw material. . According to the present invention, the aluminate phosphor has a composition formula x ¹ M ¹ O · y ¹ MgO · z ¹ Al ₂ O ₃ (M ¹ is at least one metal element selected from the group consisting of Ba, Sr and Ca) 0.5 ≦ x ¹ ≦ 4.5, 0 ≦ y ¹ ≦ 4, 0.5 ≦ z ¹ ≦ 20) as a base, and Eu and / or Mn as an activator A method for producing the above-described aluminate phosphor is provided. Further, according to the present invention, the aluminate phosphor has a composition formula x ² CeO _1.5 · y ² M ² O · z ² Al ₂ O ₃ (M ² is Mg and / or Mn, and 0.9 ≦ x ² ≦ 1.1, 0.9 ≦ y ² ≦ 1.1, z ² is 5.5) and the aluminate phosphor containing Tb and / or Mn as an activator as a substrate A manufacturing method is provided. The present invention also provides an aluminate phosphor containing 80% by mass or more of particles having a primary particle size of 0.05 μm or more and 0.3 μm or less. The present invention also provides a vacuum ultraviolet light-excited light emitting device using the above phosphor. Furthermore, the present invention provides an aluminate phosphor that contains 80% by mass or more of particles having a primary particle size of 0.05 μm or more and 0.3 μm or less and transmits visible light.
The average primary particle size is a number average value of particle sizes obtained from a photograph taken with a scanning electron microscope.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The aluminate phosphor of the present invention is an aluminate phosphor excluding the phosphorescent material.
In the method for producing an aluminate phosphor of the present invention, the range of the average primary particle diameter of the raw α-alumina powder is 0.05 μm or more and less than 0.3 μm, preferably 0.07 μm or more and 0.28 μm. More preferably, it is 0.1 μm or more and 0.25 μm or less. When the average primary particle diameter of the raw α-alumina powder is less than 0.05 μm, it is difficult to synthesize the aluminate phosphor, and when it is 0.3 μm or more, the light transmittance decreases. This is not suitable for applications such as attaching a phosphor layer to the front plate.
[0011]
In order to increase the emission luminance of the aluminate phosphor, the alumina purity of the raw material α-alumina powder is preferably 99.9% by mass or more.
[0012]
The aluminate phosphor in the present invention is represented by the composition formula x ¹ M ¹ O · y ¹ MgO · z ¹ Al ₂ O ₃ (M ¹ is at least one metal element selected from the group consisting of Ba, Sr and Ca). A phosphor containing Eu and / or Mn as an activator can be given as a substrate, and in this case, 0.5 ≦ x ¹ ≦ 4.5, 0 ≦ y ¹ ≦ 4, 0 It is preferable that 5 ≦ z ¹ ≦ 20.
[0013]
As the aluminate phosphor in the present invention, Eu and / or Mn as an activator using a composite oxide represented by the composition formula x ¹¹ (Ba, Sr) O · y ¹¹ MgO · z ¹¹ Al ₂ O ₃ as a substrate. In this case, 0.9 ≦ x ¹¹ ≦ 1.7, 1.5 ≦ y ¹¹ ≦ 2.1, and z ¹¹ is preferably 8. The content of this case Eu is 0.01 × ¹¹ or 0.2x ¹¹ or less, the Mn content is preferably in the range of 0.15Y ¹¹ below.
[0014]
As the aluminate phosphor in the present invention, a fluorescence containing Eu and / or Mn as an activator based on a complex oxide represented by the composition formula x ¹² (Ba, Ca) O.z ¹² Al ₂ O ₃ In this case, it is preferable that 1.0 ≦ x ¹² ≦ 1.5 and z ¹² is 6. The content of this case Eu is 0.01 × ¹² or more 0.15X ¹² or less, the Mn content is preferably in the range of 0.20X ¹² below.
[0015]
Examples of the aluminate phosphor in the present invention include a phosphor containing a composite oxide represented by the composition formula x ¹³ SrO.z ¹³ Al ₂ O ₃ as a substrate and Eu and / or Mn as an activator. In this case, x ¹³ is preferably 3.9 ≦ x ¹³ ≦ 4.1 and z ₁₃ is 7. In this case, the Eu content is preferably 0.02 × ¹³ or more and 0.06 × ¹³ or less, and the Mn content is preferably 0.1 × ¹³ or less.
[0016]
As the aluminate phosphor in the present invention, a complex oxide represented by the composition formula x ² CeO _1.5 · y ² M ² O · z ² Al ₂ O ₃ (M ² is Mg and / or Mn) is used as a substrate, and Tb and / or Mn can be a compound containing as an activator, where ^{0.9 ≦ x 2 ≦ 1.1,0.9 ≦ y} 2 ≦ 1.1, z 2 is a 5.5 It is preferable. The content of this Tb is 0.3x ² or more 0.5x ² or less, the Mn content is preferably in the range of 0.15Y ² below.
[0017]
The compound powder of Ba, Sr, Ca, Mg, and Ce used as the raw material of the aluminate is a compound that can be decomposed into an oxide by being decomposed at high temperature, such as hydroxide, carbonate, nitrate, halide, oxalate, or the like. Oxides can be used.
[0018]
As raw materials for Eu, Mn, and Tb, which are activators, compounds that can decompose into oxides at high temperatures, such as hydroxides, carbonates, nitrates, halides, and oxalates, or oxides can be used.
[0019]
In the method of the present invention, as a method for mixing the raw materials, a method such as a ball mill, a V-type mixer, or a stirrer that is usually used industrially can be used.
[0020]
In the method of the present invention, the aluminate phosphor can be obtained by firing the mixed raw materials in the temperature range of 900 ° C. to 1600 ° C. for 0.5 to 50 hours. When using raw materials such as hydroxides, carbonates, nitrates, halides, oxalates, etc. that can decompose at high temperatures to form oxides, a temporary temperature range of 600 ° C. to 800 ° C. is necessary before the main firing. It is also possible to bake. . In firing, for example, the raw material can be filled in an alumina boat and fired at a predetermined temperature in a predetermined gas atmosphere. If necessary, the phosphor of the present invention having better crystallinity and higher luminance may be obtained by mixing a reaction accelerator (flux) such as boron oxide or aluminum fluoride with the raw material.
[0021]
The phosphor obtained by the above method can be pulverized using a ball mill, jet mill or the like, washed with water or the like, and classified as necessary. In order to increase the crystallinity of the obtained phosphor, re-baking can be performed as necessary.
[0022]
For example, when a raw material mixed and prepared for a blue light-emitting phosphor (BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₄ O ₂₃ : Eu, etc.) is fired, a temperature range of 1000 ° C. to 1700 ° C. in a reducing atmosphere, 0 It is preferable to fire at least once in the range of 5 to 50 hours. Examples of a method for obtaining a reducing atmosphere include a method of placing graphite in a boat filled with raw materials, and a method of firing in a mixed atmosphere of nitrogen and hydrogen or a rare gas and hydrogen. Further, water vapor may be contained in these atmospheres.
[0023]
Moreover, when firing the raw material mixed and prepared for the green light emitting phosphor (BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, etc.), a temperature range of 1000 to 1700 ° C. in an air atmosphere or an oxygen atmosphere, Conditions for firing at least once in the range of 0.5 to 40 hours are preferable.
[0024]
The aluminate phosphor of the present invention contains 80% by mass or more of particles having a primary particle size of 0.05 μm or more and 0.3 μm or less, preferably a particle having a primary particle size of 0.07 μm or more and 0.28 μm or less. Is less than the primary particle diameter of the aluminate phosphor obtained by a normal method and has few coarse particles. Thus, the emission luminance is increased by reducing the primary particle diameter of the phosphor and reducing the coarse particles. Further, for example, the phosphor can be efficiently applied in a minute discharge space such as a display cell of a PDP, and various light emission type displays such as a PDP having high emission luminance can be manufactured.
[0025]
In addition, when the phosphor is applied to the front plate of the PDP, it is extremely suitable for an application that requires the particles to transmit visible light. The aluminate phosphor of the present invention preferably contains 80% by mass or more of particles having a primary particle size of 0.05 μm or more and less than 0.3 μm, which seems to be because most of the particles are smaller than the wavelength of visible light. However, since it can transmit visible light, it is extremely suitable for applications that transmit visible light.
[0026]
Since the aluminate phosphor obtained by the present invention has a small primary particle size and few coarse particles, it has excellent emission characteristics particularly under vacuum ultraviolet excitation, and can be used for various displays such as PDP. It is extremely useful as a phosphor for a device. In addition, the aluminate phosphor in the present invention exhibits excellent light emission characteristics not only under vacuum ultraviolet light excitation but also under ultraviolet light, cathode ray or X-ray excitation.
That is, the present invention provides a method for producing an aluminate phosphor that can be excited by a wide range of energy such as vacuum ultraviolet rays, ultraviolet rays, cathode rays, or X-rays and exhibits excellent light emission characteristics.
[0027]
In the aluminate phosphor in the present invention, the aggregation of primary particles is weak, and subsequent processes such as pulverization can be simplified.
[0028]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In this example, the particles were produced by the method disclosed in JP-A-7-206430 and consisted of particles having substantially no crushed surface, the purity was 99.99 mass%, and the average primary particle size was 0. .2 μm α-alumina powder was used as a raw material.
In this example, the average primary particle size of the α-alumina powder and the phosphor powder is measured by image analysis of a photograph of the powder obtained using a scanning electron microscope (JSM-T220 type manufactured by JEOL Ltd.). Was done.
[0029]
Example 1
7.23 g of α-alumina having an average primary particle size of 0.2 μm, 2.52 g of barium carbonate, 0.25 g of europium oxide, and 1.38 g of basic magnesium carbonate were mixed by a ball mill, and the resulting mixture was charged into an alumina boat. Then, it was calcined at 1450 ° C. for 2 hours in a weak reducing atmosphere consisting of 2 volume% hydrogen and 98 volume% argon to obtain a powder. As a result of measuring the primary particle diameter using a scanning electron micrograph of the obtained powder, the primary particle diameter of all the particles of the obtained powder was 0.3 μm or less. The average primary particle diameter of the obtained powder was 0.2 μm. By X-ray diffraction measurement (micro X-ray diffractometer: phase identification evaluation by Ru-200 manufactured by Rigaku Corporation), the obtained powder was a BaMgAl ₁₀ O ₁₇ : Eu single phase blue-emitting aluminate phosphor. It was found to be a powder.
[0030]
This blue light-emitting phosphor was irradiated with ultraviolet rays using an excimer 146 nm lamp (manufactured by Ushio Electric) in a vacuum chamber of 6.7 Pa (5 × 10 ⁻² Torr) or less, and a color luminance meter (BM-CON manufactured by TOPCON) was used. When the luminance was measured using 7 type), strong blue light emission was shown, and the light emission luminance was 28.1 cd / m ² . In addition, even when this phosphor was excited by ultraviolet rays of 254 nm or 365 nm, high luminance blue light emission was exhibited in both cases.
[0031]
Comparative Example 1
Except for using α-alumina having an average primary particle size of 0.7 μm, phosphor powder was obtained in the same manner as in Example 1, and was obtained in a vacuum chamber of 6.7 Pa (5 × 10 ⁻² Torr) or less. When irradiated with ultraviolet rays using an excimer 146 nm lamp (manufactured by USHIO INC.), The light emission luminance was 25.1 cd / m ² .
[0032]
【The invention's effect】
According to the present invention, it is possible to produce an aluminate phosphor having a small primary particle diameter, extremely weak aggregation between primary particles, and high emission luminance. This aluminate phosphor is extremely useful industrially as a phosphor used in various displays such as PDP and vacuum ultraviolet light-excited light emitting devices such as rare gas lamps.

Claims (5)

  The manufacturing method of the aluminate fluorescent substance (except the aluminate fluorescent substance for phosphorescent materials) characterized by using the alpha alumina powder whose average primary particle diameter is 0.05 micrometer or more and less than 0.3 micrometer as a raw material.   2. The method for producing an aluminate phosphor according to claim 1, wherein the [alpha] -alumina powder comprises [alpha] -alumina particles having substantially no crushing surface.   The method for producing an aluminate phosphor according to claim 1 or 2, wherein the purity of the α-alumina powder is 99.9% by mass or more. The aluminate phosphor has a composition formula x ¹ M ¹ O · y ¹ MgO · z ¹ Al ₂ O ₃ (M ¹ is at least one metal element selected from the group consisting of Ba, Sr and Ca; 5. A composite oxide represented by 5 ≦ x ¹ ≦ 4.5, 0 ≦ y ¹ ≦ 4, 0.5 ≦ z ¹ ≦ 20) is used as a base, and Eu and / or Mn is contained as an activator. The manufacturing method of the aluminate fluorescent substance in any one of -3. The aluminate phosphor has a composition formula x ² CeO _1.5 · y ² M ² O · z ² Al ₂ O ₃ (M ² is Mg and / or Mn, 0.9 ≦ x ² ≦ 1.1, 0 .9 ≦ y ² ≦ 1.1, z ² = 5.5) as a base, and containing Tb and / or Mn as an activator. Method for producing aluminate phosphor.